Safety polish rod stop



July 23, 1935. G, w

SAFETY POLISH ROD STOP Filed May 14, 1954 Zr/ 9 M /Nl EN 70 .m wd w; 5

Patented July 23, 1935 UNlTED STATES PATENT OFF-ICE.

2,008,806 I I SAFETY POLISH Ron. STOP, Gould Wells, Gila Bend, Ariz. Application May 14, 1934, Serial No. 725,525

3 Claims.

My invention relates toimprovements in safety polish rod stops, for use on oil or other deep well pumps to prevent damage to the lower pump parts whenever the reciprocating mechanism gives way. This device is not to beconfused with sucker rod supports used in handling sucker rods in and out of wells, or with polish rod grips used to connect the walking beam reins to the polish rod.

The objects of this invention are first, to provide an easily adjustable stop which; may be attached to the polish rod below the polish rod grip and above the lower limit of travel of the rod; second, to provide means whereby the stop will firmly grip and hold the polish rod at a predetermined position whenever the mechanism above the stop gives way. Other objects will appear hereinafter.

I accomplish these objects by means of the mechanism and devices illustrated in the ac-' All parts of the device, as hereinafter described,

are made preferably of steel. The spider 2 is illustrated as resting on the pump-head 3, but it is obvious that the lower part of the spider may be threaded to screw directly into the top of the pump-head. The lower portion of the spider 4 is drilled to receive the polish rod loosely, or with an easy sliding fit, and the upper portion has a tapered opening 6, the sides of which cooperate with taper of slips 8 to form a slip seat. The slips are held in place upon the polish rod by a stop collar 9 surrounding the polish rod and having a cylindrical bore l0 forming an annular cavity into which the upper portions of the slips may be received and retained. These upper portions are shaped so that each has an arcuate periphery adapted to fit withina proportionate part of cavity [0 while their lower portions have a rounding taper 1 adapted to fit into, co-operate with, and substantially conform to the female taper bore or slip seat 6 in the spider. In the aggregate, aside from the inter-spaces 20 to allow for take-up, the upper portions of theslips form a cylinder surrounding the polish rod and conformable to the annular cavity In in the stopcollar, and the lower portions form a segmental slipv stop."

Set screws ll threaded thru stop-collar 9 bear upon slips &and' firmly clamp them upon the polish'fodQ Each slip is provided with a drilled cavity N5 of somewhat larger diameter than the end of the set screw operative therein so that when in register the slips will hang in place when the set screws are slightly loosened thus enabling adjustments to be easily made. These cavities are large enough and positioned so that when the stop is actuated the upper ends of the slips bear on the upper domed top l3 of cylindrical cavity l0 and do not tend to shear the ends of the set screws.

The groove I! on the inner face of the slips may be plain or provided with serrations l8 to. form wickers as shown particularly in Figure l- The spider 2 is provided with trunnions M to aid in handling the assembly after the stop has actuated and set. i

In operation the spider is placed upon or attached to the pump-head as above mentioned, and the upper stop collar with the slips in place is secured in position onthe polish rod by tightening the set screws ll, above the lower limit of the travel of the rod.

The set screws, while exerting considerable force, are not intended to sustain the weight of the polish rod when the device is actuated, but are primarily intended to hold the slips in place and resultantly hold the stop collar in place upon the polish rod. 7 7

Now, in case any portion of the pumping machinery above the stop gives way, the stop collar and slips drop into position upon and within the spider. This pbsition is indicated by the dotted outline I9, Figure 1. The wedging action of the cooperating tapers forces the slips tightly onto the polish rod and the assembly thus formed holds the polish rod in place above the pump head and prevents it and the attached sucker rods from falling further and damaging the valves. and easing of the pump.

While I have shown the slips as consisting of two parts only, it is obvious that any plural numher may be used, depending on the size of the manner repairs can be made and then reins may be attached to the trunnions l4 and the assembly, including the polish rod itself, raised to operative position.

I claim:--

1. A well pump polish rod safety stop comprising, in combination, a spider adapted to rest on the pump head having a downwardly diminishing taper bore to form a slip seat, a stop collar provided with a downwardly facing cavity adapted to receive the upper ends of a plurality of slips, means for retaining the upper portions of said slips within said cavity and positioning said collar upon the polish rod above said spider, and a plurality of slips surrounding the said polish rod having the upper portions shaped to: fit within the cavity in said stop collar and be retained therein.

2. A well pump polish rod safety stop comprising, in combination, a spider adapted to rest on the pump head, having a downwardly diminishing taper bore forming a slip seat, a stop collar posi tioned on the polish rod. above said spider having an upwardly extending annular cavity adapted to receive the upper portions of a plurality of slips, means for retaining said slips within said annular cavity, a plurality of slips having their upper portions rounded to fit within the cylindrical cavity in said stop collar and be retained therein, whereby said stop collar is positioned upon the polish rod.

3 A well pump polish rod safety stop, comprising in combination, a spider adapted to rest on the pump head having a downwardly diminishing taper bore forming a slip seat, a stop collar adapted to be positioned on the polish rod above said spider having an upwardly extending cylindrical bore forming an annular cavity around the polish rod and terminating upwardly with a domed top face, set screws radially positioned in the sides of said stop collar and adapted to bear upon the upper portions of. slips fitting within said annular cavity, a plurality of slips surrounding said polish 

